Wheat bran components modulate intestinal bacteria and gene expression of barrier function relevant proteins in a piglet model.

The objective of this study was to determine the impact of wheat bran and its main polysaccharides on intestinal bacteria and gene expression of intestinal barrier function relevant proteins. Thirty freshly weaned male piglets were assigned randomly to five dietary treatment groups with six piglets per group. Accordingly, five synthetic diets including a basal control diet without fiber components (CON), wheat bran diet (10% wheat bran, WB), arabinoxylan diet (AX), cellulose diet (CEL) and combined diet of arabinoxylan and cellulose (CB) were studied. The piglets were fed ad libitum for 30 d. Lower Escherichia coli (E. coli) populations in WB group and higher probiotic (Lactobacillus and Bifidobacterium) populations in groups fed diets containing arabinoxylan (WB, AX and CB) were observed and compared with CON group. Compared with CON group, the gene expressions of cystic fibrosis transmembrane conductance regulator (CFTR), calcium-activated chloride channel regulator 1 (CLCA1) and voltage-gated chloride channel 2 (CIC2) were suppressed in the WB group. And wheat bran down-regulated gene expression of pro-inflammation (TNF-α, IL-1ß, IL-6) and TLRs/MyD88/NF-κB pathway compared with CON group. In conclusion, wheat bran and its main polysaccharides could change intestinal microflora and down-regulate the gene expression of intestinal barrier function relevant proteins in the distal small intestinal mucosa.

Arabinoxylan in wheat is more responsible than cellulose for promoting intestinal barrier function in weaned male piglets.

BACKGROUND: The effect of dietary fiber on intestinal function primarily has been ascribed to its interaction with intestinal bacteria in the hindgut, whereas changes in intestinal bacteria in the host have been considered to depend on fiber composition. OBJECTIVES: The objectives of this study were to determine the contribution of the major fiber components to the health-promoting effects of wheat bran on intestinal mucosal barrier function and to elucidate the involvement of microbiota changes in weaned piglets. METHODS: Thirty freshly weaned male piglets were assigned to 5 dietary treatment groups (n = 6) according to litter and weight. The piglets consumed synthetic diets ad libitum for 30 d, including a basal control diet (CON) without fiber components, a wheat bran diet (WB) as reference diet (10% wheat bran), and 3 other diets containing amounts of fiber components equivalent to those in the WB, i.e., an arabinoxylan diet (AX), a cellulose diet (CEL), and a combined arabinoxylan and cellulose diet (CB). RESULTS: The groups consuming diets containing arabinoxylans (i.e., the WB, AX, and CB groups) had increased intestinal secretory immunoglobulin A concentrations, goblet cell number and cecal short-chain fatty acid concentrations, and reduced branched-chain fatty acid concentrations and pH values compared with the CON group. In the WB group, the stimulated secretion of Cl(-) was suppressed (60.8% and 47.5% change in short-circuit current caused by theophylline and carbachol, respectively) in the distal small intestine compared with the CON group. The AX and CB groups also had increased intestinal alkaline phosphatase activities and reduced intestinal transcellular permeability (by 77.3% and 67.2%, respectively) compared with the CON group. Meanwhile, in the WB group, cecal Bacteroidetes and Enterobacteriaceae populations were lower, and the growth of Lactobacillus was higher in the AX and CB groups than in the CON group, whereas no positive effect on intestinal barrier function was observed in the CEL group. CONCLUSION: Arabinoxylan in wheat bran, and not cellulose, is mainly responsible for improving various functional components of the intestinal barrier function and the involvement of microbiota changes.

Effect of different dietary non-starch fiber fractions on growth performance, nutrient digestibility, and intestinal development in weaned pigs.

OBJECTIVES: This study explored the effects of different fiber fractions on growth performance, nutrient digestibility and intestinal development in a porcine model. METHODS: Blood and tissue samples were collected from thirty-two weaned pigs fed with control diet (CON) or diet containing 5 % cellulose (CEL), xylan (XYL) or ß-glucan (GLU). RESULTS: This reserch showed that GLU supplementation decreased the growth performance of pigs (P <0.05). The digestibility of gross energy, ash and crude fiber were higher in the XYL group than that in the GLU and CEL group (P <0.05). NSPs supplementation decreased serum glucose concentration (P <0.05). However, the serum superoxide dismutase and glutathione concentrations were elevated in GLU group (P <0.05). GLU supplementation not only increased the ratio of villus height/crypt depth in duodenum and ileum (P <0.05), but also elevated the activity of sucrase in the jejunum and ileum compared to CEL group (P <0.05). Interestingly, both XYL and GLU group showed higher expression levels of genes associated with intestinal barrier functions (zonulaoccludens 1 and claudin 1) and nutrient transportation (Na+-glucose co-transporter 1 and facilitated glucose transporter 2). Moreover, pigs on XYL-containing diet showed higher abundance of Bifidobacterium than the GLU group in the ileum and cecum (P <0.05). CONCLUSIONS: This study not only indicated how the gut digestive physiology adapted to different NSP fractions, but also provided novel (to our knowledge) information that could promote our understanding of the role of dietary fibers in maintaining gut health.